How to run multiple Django apps in production at the same Apache server

I have a practical problem - I'm building a web site, but I have one app already running in production for the site. So I need to take care that I don't lose the data in my app and make sure that 2 apps work together.

Kalle Tolonen
June 7, 2022
Last updated on June 13, 2022

Configuration
-Debian 11
-Apache2 2.4
  

Working the process out locally

  
It's good to try out things locally first and only after that works, apply the changes to a production environment. So, in order to do that I copied my soon-to-be-implemented app from my dev location to my website's project folder.  
     

cp shopping/shopping/list/ /home/kallet /kalletolonencom/ktcom/

  
After that was done, it was time to add the app to settings and run the migrations.     

micro settings.py

     

#settings.py

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'mainsite',
    'markdownx',
    'list', #added my app
]

  
After trying out the url for my app I had an error message that guided me towards urls.py.      

 Using the URLconf defined in ktcom.urls, Django tried these URL patterns, in this order: 

     
I modified urls.py.   

from django.conf.urls import include, url #added this

#SHOPPINGLIST
    url('', include('list.urls')), #and this

  
After that I ended up with a great error message that pointed me to list/urls.py, to where I just copied my old urls from that project's urls.py.   

ModuleNotFoundError: No module named 'list.urls'

  
The only error left was the one that complained about the admin namespace, since my project already had an admin path.     

?: (urls.W005) URL namespace 'admin' isn't unique. You may not be able to reverse all URLs in this namespace

  
So naturally I removed that from my list-app and tested the functionality.   

     

Production install & changing the DBMS to a better one

  
You can read my article on this process here and apply it to your project.   
While doing the production DBMS update I ran into some challenges and the error message that led me to a working solution was:     

Could not load contenttypes.ContentType(pk=7): duplicate key value violates unique constraint

  
The thing to notice is that you should exclude some things from your data dump, I found a nice answer on this source on the parameters.   
./manage.py dumpdata --exclude auth.permission --exclude contenttypes > db.json